System and method for using a wireless enabled portable computer system as a wireless modem

ABSTRACT

A method and system for using a wireless enabled portable computer system as a wireless modem. The portable computer system may be a personal digital assistant (PDA) having an internal wireless modem. The internal wireless modem, e.g., GSM radio, contains a communication port (port2) that communicates with a processor of the portable computer system. The portable computer system also contains another communication port (port1) that is externally available for connection to a second computer system. A software bridge is provided that copies commands and/or data from the port1 over to the port2 and vice-versa. The software bridge allows the second computer system to directly use the internal wireless modem of the portable computer system when the portable computer system is connected to the second computer. The connection to the second computer system can be made by a wired connection (e.g., serial interface, RS232) or by a wireless connection, e.g., Bluetooth or infra-red communication. The port1 and the port2 can be serial communication ports which may be UART compliant. The PDA thus extends wireless functionality to a second computer system (e.g., a notebook) using conventional connection mechanisms for communicating with the second computer system.

This is a continuation of copending application Ser. No. 09/801,532filed on Mar. 7, 2001 now U.S. Pat. No. 6,745,047 which is herebyincorporated by reference to this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of data processing. Morespecifically, embodiments of the present invention relate to wirelesscommunication using a portable computer system and a second (“host”)computer system.

2. Related Art

As the components required to build a computer system have reduced insize, new categories of electronic devices and computer systems haveemerged. One of the new categories of computer systems is the “palmtop”computer system. A palmtop computer system is a computer that is smallenough to be held in the hand of a user and can therefore be“palm-sized.” Most palmtop computer systems are used to implementvarious Personal Information Management (PIM) applications such as anaddress book, a daily organizer (calendar, datebook, etc.) andelectronic notepads, to name a few. Palmtop computers with PIM softwarehave been know as Personal Digital Assistants (PDAs). Many PDAs have asmall and flat display screen associated therewith.

User convenience and device value are very important factors forportable electronic devices. Typically, portable electronic devices areemployed while the user is on the run, e.g., in business meetings, onbusiness travel, personal travel, in a vehicle, on foot, etc. Becausethe user may be occupied or busy while using the portable electronicdevice, the number of user steps or user tasks required in order toaccess information from an electronic device (or to store informationinto the electronic device) is crucial for producing a commerciallysuccessful and useful product. That is, the more difficult it is toaccess data from an electronic device, the less likely the user willperform those tasks to obtain the information. Likewise, the easierinformation is to obtain, the more likely the portable electronic devicewill be used to obtain that information and the more likely the portableelectronic device will become a part of the user's everyday activities.

Similarly, the more useful the device, the more the device will be usedand acquired. The functionality of mobile wireless devices is undergoinga transition. Mobile devices are evolving from a single applicationdevice with dedicated specific purpose communication channel (forexample, a cell phone or pager), to more general-purpose devices withmore flexible data communication capabilities.

More specifically, wireless technology is advancing, both in the numberof options that are available for providing connectivity, and in theirflexibility to provide general purpose data communication. Differenttechnologies such as cellular technologies (e.g., CDMA, TDMA), LANaccess technologies (e.g., IEEE 802.11, HomeRF) and PAN technologies(e.g., Bluetooth, IR) each address a different set of needs, and providedifferent set of potential services. Mobile devices are no longer alsorestricted to one communication channel. Modular mobile devices allownetwork interfaces to be attached, allowing for unlimited communicationsconfigurations. In addition, Bluetooth technology allows a single mobiledevice to be simultaneously in access multiple piconets through a singleinterface.

To facilitate mobile wireless communication, several wireless modemperipheral devices are available that can be directly connected to theserial interface port of a host computer system thereby providingwireless communication to the host computer system, e.g., a laptopcomputer. The serial interface on the wireless modem peripheral isreserved for this type of connection. Additionally, some cell phoneshaving built-in modems also provide an interface that is reserved forthe host computer system thereby providing wireless communication to thehost computer system. However, cell phone interfaces tend to be complexand non-standard. Few computer users have the required cabling to makethem work. As cellular phone functionality and wireless modemfunctionality are integrated into PDAs, a problem has arisen in thatconventional PDAs heretofore do not offer a convenient (or any)mechanism for providing wireless communication to a host computer systemusing their internal resources as do conventional cell phones andwireless modem peripherals.

SUMMARY OF THE INVENTION

Accordingly, what is needed is a method and system allowing a PDA to useits internal resources to act as a peripheral device for a connectedhost computer system. Further, what is needed is a system and methodallowing a PDA to provide wireless communication functionality to aconnected host computer system using its internal wireless modem. Whatis also needed is such a system that does not require any additionalphysical connection resources (to the host computer system) that are notalready present in the equipment of a conventional PDA. What is furtherneeded is a mechanism that allows a host computer system to use aconnected PDA as a wireless modem peripheral. Using such a method andsystem, a PDA could extend wireless functionality to a host computersystem and thus increase the value of the PDA to the user. Embodimentsof the present invention provide the above advantages and others notspecifically mentioned above but described in the sections to follow.

A method and system are described for using a wireless enabled portablecomputer system as a wireless modem. The portable computer system may bea personal digital assistant (PDA) having an internal wireless modem.The internal wireless modem, e.g., GSM radio in one embodiment, containsa communication port (port2) that communicates with a processor of theportable computer system. The portable computer system also containsanother communication port (port1) that is externally available forconnection to a second computer system. A software bridge is providedthat copies commands and/or data from the port1 over to the port2 andvice-versa.

The software bridge allows the second computer system to directly usethe internal wireless modem of the portable computer system when theportable computer system is connected to the second computer system. Theconnection to the second computer system can be made by a wiredconnection (e.g., serial interface, RS232) or by a wireless connection,e.g., Bluetooth or infra-red communication. The port1 and the port2 canbe serial communication ports which may be UART compliant. The PDA thusextends wireless functionality to a second computer system (e.g., anotebook) using conventional connection mechanisms for communicatingwith the second computer system. In one embodiment, any wirelesslyenabled PDA can be placed in its cradle (which is coupled to a hostcomputer system) and can readily be used as a wireless modem peripheralby the host computer system.

Regarding other embodiments, in the case where the second or “host”computer system is a PPP (point-to-point protocol) client and thewireless communication is not PPP compliant, the internal modem mayprovide translation to the PPP protocol. In this case, the processorreceives PPP compliant communication. Alternatively, the software bridgemay provide this translation if the internal modem provides non-PPPinformation to the processor.

More specifically, an embodiment of the present invention includes apersonal digital assistant comprising: a first communication portaccessible from an external communication connector, the externalcommunication connector for coupling with a host computer system; aninternal wireless communication device configured to communicate with asecond communication port that is internal to the personal digitalassistant and wherein the second communication port is not directlyaccessible by the external communication connector; a memory; and aprocessor coupled to communicate with the first communication port andthe second communication port and coupled to the memory, the processoroperable to make the internal wireless communication device accessibleto the host computer system by executing instructions stored in thememory that implement a communication bridge providing communicationbetween the first communication port and the second communication port.

Another embodiment of the present invention includes a computer systemcomprising: a host computer system; a portable computer systemcommunicatively coupled to the host computer system and comprising: afirst communication port directly accessible from an externalcommunication device, the external communication device forcommunicating with the host computer system; an internal wirelesscommunication device configured to communicate with a secondcommunication port that is internal to the portable computer system andthat is not directly accessible by the external communication device; amemory; and a processor coupled to communicate with the firstcommunication port and the second communication port and coupled to thememory, the processor operable to make the internal wirelesscommunication device accessible to the host computer system by executinginstructions stored in the memory that implement a communication bridgebetween the first communication port and the second communication port.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is system illustration of a palmtop or “palm sized” computersystem connected to other computer systems and the Internet via a cradledevice.

FIG. 2A is a top side perspective view of an exemplary palmtop computersystem.

FIG. 2B is a bottom side perspective view of the exemplary palmtopcomputer system of FIG. 2A.

FIG. 2C is a perspective top view of another embodiment of the exemplarypalmtop computer system.

FIG. 3 is an exploded view of the components of an exemplary palmtopcomputer system of FIG. 2A.

FIG. 4 is a perspective view of a cradle device for connecting a palmtopcomputer system to other systems via a communication interface.

FIG. 5 is a logical block diagram of an exemplary palmtop computersystem in accordance with an embodiment of the present invention.

FIG. 6A illustrates a hardware diagram of a system in accordance withthe present invention including a portable computer system coupled to asecond or “host” computer system and providing peripheral support forthe host computer system.

FIG. 6B illustrates a logical system diagram in accordance with thepresent invention including a portable computer system having a softwarebridge and coupled to a second or “host” computer system and providingperipheral support for the host computer system.

FIG. 7 is a flow diagram illustrating steps in accordance with thesoftware bridge of one embodiment of the present invention for providingperipheral modem support for a connected host computer system.

FIG. 8 is a communication protocol diagram in accordance with oneembodiment of the present invention having a PPP communication frameworkend-to-end.

FIG. 9 is a communication protocol diagram in accordance with oneembodiment of the present invention where the internal modem of theportable computer system performs NON-PPP to PPP translation for the PPPclient.

FIG. 10 is a communication protocol diagram in accordance with oneembodiment of the present invention where the software bridge of theportable computer system performs NON-PPP to PPP translation for the PPPclient.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the present invention, a methodand system for using a wireless enabled portable computer system as awireless modem peripheral for a host computer system, numerous specificdetails are set forth in order to provide a thorough understanding ofthe present invention. However, it will be recognized by one skilled inthe art that the present invention may be practiced without thesespecific details or with equivalents thereof. In other instances, wellknown methods, procedures, components, and circuits have not beendescribed in detail as not to unnecessarily obscure aspects of thepresent invention.

Notation and Nomenclature

Some portions of the detailed descriptions which follow (e.g., process400 of FIG. 7) are presented in terms of procedures, steps, logicblocks, processing, and other symbolic representations of operations ondata bits that can be performed on computer memory. These descriptionsand representations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. A procedure, computer executed step, logicblock, process, etc., is here, and generally, conceived to be aself-consistent sequence of steps or instructions leading to a desiredresult. The steps are those requiring physical manipulations of physicalquantities. Usually, though not necessarily, these quantities take theform of electrical or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated in a computersystem. It has proven convenient at times, principally for reasons ofcommon usage, to refer to these signals as bits, values, elements,symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the followingdiscussions, it is appreciated that throughout the present invention,discussions utilizing terms such as “checking,” “accessing” or“processing” or “computing” or “suspending” or “resuming” or“translating” or “calculating” or “determining” or “scrolling” or“displaying” or “recognizing” or “executing” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

Exemplary Palmtop Computer System Platform

The processes of the present invention described herein are particularlyapplicable to portable computer systems called personal digitalassistants (PDA). These devices include, for instance, intelligent cellphones, computerized pagers and portable computer systems. Althoughapplicable across a wide variety of platforms and devices, the presentinvention is described herein by example with respect to a portable ormobile computer system.

FIG. 1 illustrates an exemplary networked system 50 that can be used inconjunction with an embodiment of the present invention. System 50 isexemplary only and comprises a host computer system 56 which can eitherbe a desktop unit as shown, or, alternatively, can be a laptop system58. Optionally, one or more host computer systems can be used withinsystem 50. Host computer systems 58 and 56 are shown connected to acommunication bus 54, which in one embodiment can be a serialcommunication bus, but could be of any of a number of well knowndesigns, e.g., a parallel bus, Ethernet Local Area Network (LAN), etc.Optionally, bus 54 (or a separate communication channel) can providecommunication with the Internet 52 using a number of well knownprotocols.

Importantly, a communication link is also coupled to a cradle 60 (orcable dock) for receiving and initiating communication with an exemplarypalmtop (“palm-sized”) portable computer system 100 over line 265.Cradle 60 provides an electrical and mechanical communication interfacebetween the computer system 100 for two way communications. In oneembodiment, the communication link including cradle 60 and line 265 is aserial communication link or can be a USB link. Computer system 100 mayalso contain a wireless infrared communication mechanism 64 for sendingand receiving information to or from other devices. As discussed morefully below, computer system 100 also contains one or more otherwireless communication mechanisms, e.g., cellular phone, Bluetoothand/or wireless LAN (e.g., IEEE 802.11), for instance, all of which canbe used to establish the communication link between the portablecomputer system 100 and the host computer system. As described furtherbelow, embodiments of the present invention facilitate the use of theportable computer system 100 as a peripheral to the host computer systemthereby leveraging the communication link between the two devices.

FIG. 2A is a perspective illustration of the top face 100 a of oneembodiment of the palmtop computer system. The top face 110 a contains adisplay screen 105 surrounded by a bezel or cover. A removable stylus 80is also shown. The display screen 105 contains a transparent touchscreen (digitizer) able to register contact between the screen and thetip of the stylus 80. The stylus 80 can be of any material to makecontact with the screen 105. As shown in FIG. 2A, the stylus 80 isinserted into a receiving slot or rail 350. Slot or rail 350 acts tohold the stylus when the computer system 100 a is not in use. Slot orrail 350 may contain switching devices for automatically powering downand automatically power up computer system 100 a based on the positionof the stylus 80. The top face 100 a also contains one or more dedicatedand/or programmable buttons 75 for selecting information and causing thecomputer system to implement functions. Other buttons (icons) can beimplemented within a silk screen layer material 84 on which regions 106a and 106 b reside. An exemplary on/off button 95 is also shown.

FIG. 2A also illustrates a handwriting recognition pad or “digitizer”containing two regions 106 a and 106 b. Region 106 a is for the drawingof alpha characters therein for automatic recognition (and generally notused for recognizing numeric characters) and region 106 b is for thedrawing of numeric characters therein for automatic recognition (andgenerally not used for recognizing numeric characters). The stylus 80 isused for stroking a character within one of the regions 106 a and 106 b.The stroke information is then fed to an internal processor forautomatic character recognition. Once characters are recognized, theyare typically displayed on the screen 105 for verification and/ormodification.

The digitizer 160 records both the (x, y) coordinate value of thecurrent location of the stylus and also simultaneously records thepressure that the stylus exerts on the face of the digitizer pad. Thecoordinate values (spatial information) and pressure data are thenoutput on separate channels for sampling by the processor 101 (FIG. 5).In one implementation, there are roughly 256 different discrete levelsof pressure that can be detected by the digitizer 106. Since thedigitizer's channels are sampled serially by the processor, the strokespatial data are sampled “pseudo” simultaneously with the associatedpressure data. The sampled data is then stored in a memory by theprocessor 101 (FIG. 5) for later analysis.

FIG. 2B illustrates the bottom side 100 b of one embodiment of thepalmtop computer system. An optional extendible antenna 85 is shown andalso a battery storage compartment door 90 is shown. A communicationinterface 108 is also shown. In one embodiment of the present invention,the serial communication interface 108 is a serial communication port,but could also alternatively be of any of a number of well knowncommunication standards and protocols, e.g., parallel, SCSI, Firewire(IEEE 1394), Ethernet, etc. In FIG. 2B is also shown the stylusreceiving slot or rail 350.

FIG. 2C illustrates a front perspective view of another implementation100 c of the palmtop computer system. As shown, the flat central area iscomposed of a display screen area 105 and a thin silk screen layermaterial portion 84. Typically, the silk screen layer material portion84 is opaque and may contain icons, buttons, images, etc., graphicallyprinted thereon in addition to regions 106 a and 106 b. The displayscreen area 105 and portion 84 are disposed over a digitizer.

FIG. 3 is an exploded view of the exemplary palmtop computer system 100.System 100 contains a front cover 210 having an outline of region 106and holes 75 a for receiving buttons 75 b. A flat panel display 105(both liquid crystal display and touch screen) fits into front cover210. Any of a number of display technologies can be used, e.g., LCD,FED, plasma, etc., for the flat panel display 105. In one embodiment,the display 105 is a flat panel multi-mode display capable of bothmonochrome and color display modes.

The touch screen can be a digitizer. A battery 215 provides electricalpower. Replaceable cells or rechargeable batteries can be used. Wellknown electronics coupled to the battery 215 can detect the energy levelof the battery 215. This information can be sampled by the computersystem 110 (FIG. 5) using well known techniques. The digitizer of FIG. 3can be implemented using well known devices, for instance, using theADS-7846 device by Burr-Brown that provides separate channels forspatial stroke information and pressure information. A contrastadjustment (potentiometer) 220 is also shown but can also be implementedelectronically, e.g., by software, (FIG. 2C) without any manual knob.On/off button 95 is shown along with an infrared emitter and detectordevice 64. A flex circuit 230 is shown along with a PC board 225containing electronics and logic (e.g., memory, communication bus,processor, etc.) for implementing computer system functionality. Thedigitizer pad is also included in PC board 225. A midframe 235 is shownalong with stylus 80. Optional position adjustable antenna 85 is shown.The midframe 235 contains the stylus receiving slot or rail 350.

An optional radio receiver/transmitter device 240 is also shown betweenthe midframe and the rear cover 245 of FIG. 3. Device 240 may include awireless modem device and/or a wireless radio, e.g., a GSM wirelessradio with supporting chipset. The receiver/transmitter device 240 iscoupled to the antenna 85 and also coupled to communicate with the PCboard 225. In one implementation, the Mobitex wireless communicationsystem is used to provide two way communication between system 100 andother networked computers and/or the Internet via a proxy server. Inother embodiments, TCP protocol can be used. The wireless communicationcapability of system 100 can be implemented using a number of well knowntechnologies, such as, for instance, cellular phone technology,Bluetooth, wireless LAN (e.g., 802.11), etc.

FIG. 4 is a perspective illustration of one embodiment of the cradle 60for receiving the palmtop computer system 100. In other embodiments,cradle 60 is not a stand-up device but is rather part of a cableconnection between the palmtop computer system 100 and the desk topunit. Cradle 60 contains a mechanical and electrical interface 260 forinterfacing with serial connection 108 (FIG. 2B) of computer system 100when system 100 is slid into the cradle 60 in an upright position.Alternatively, a USB connection could be used. Once inserted, button 270may be pressed to initiate two way communication between system 100 andother computer systems coupled to serial communication 265.

FIG. 5 illustrates circuitry of palmtop computer system 100, some ofwhich can be implemented on PC board 225. Computer system 100 includesan address/data bus 99 for communicating information, a centralprocessor 101 coupled with the bus 99 for processing information andinstructions, a volatile memory 102 (e.g., random access memory RAM)coupled with the bus 99 for storing information and instructions for thecentral processor 101 and a non-volatile memory 103 (e.g., read onlymemory ROM) coupled with the bus 99 for storing static information andinstructions for the processor 101. Computer system 110 also includes anoptional data storage device 104 (e.g., thin profile removable memory)coupled with the bus 99 for storing information and instructions. Device104 can be removable. As described above, system 100 also contains adisplay device 105 coupled to the bus 99 for displaying information tothe computer user. PC board 225 can contain the processor 101, the bus99, the ROM 103 and the RAM 102.

Also included in computer system 110 of FIG. 5 is an alphanumeric inputdevice 106 which in one implementation is a handwriting recognition pad(“digitizer”) having regions 106 a and 106 b (FIG. 2A), for instance.Device 106 can communicate information (spatial data and pressure data)and command selections to the central processor 101. System 110 alsoincludes an optional cursor control or directing device 107 coupled tothe bus for communicating user input information and command selectionsto the central processor 101. In one implementation, device 107 is atouch screen device incorporated with screen 105. Device 107 is capableof registering a position on the screen 105 where the stylus makescontact and the pressure of the contact. The display device 105 utilizedwith the computer system 110 may be a liquid crystal device, cathode raytube (CRT), field emission device (FED, also called flat panel CRT) orother display device suitable for creating graphic images andalphanumeric characters recognizable to the user. In one embodiment, thedisplay 105 utilizes color sequential scanning but could also utilizecolor filters with subpixels.

Signal communication device 108, also coupled to bus 99, can be a serialport (or USB port) for communicating with the cradle 60. In addition todevice 108, wireless communication links can be established between thedevice 100 and a host computer system using a Bluetooth wireless device360 or an infrared device 355. The wireless modem device 240 is coupledto communicate with the processor 101 but is not directly coupled toport 108.

Wireless Communication Enabled PDA Used as Peripheral Device to HostComputer System

FIG. 6A illustrates a hardware diagram 200 a in accordance with anembodiment of the present invention where a portable computer system 100d is used as a peripheral device to a connected host computer system 56.The portable computer system 100 d may be communicatively linked to thehost computer system 56 using one of a variety of differentcommunication mechanisms 550. In one embodiment, a wired connection 265is used, e.g., a serial communication (RS/232) or a USB connection maybe used. Alternatively, the link 550 may be established using a wirelessconnection, e.g., Bluetooth or infrared communication may be used. Tosupport wired connections, an external communication device or connector108 a is present on the outside surface of device 100 d.

Different communication devices are used to support the differentcommunication mechanisms available to establish link 550. To supportBluetooth connections, an external Bluetooth communication device 360 ispresent on the outside surface of device 100 d which communicates with acorresponding device 315 on the host computer system 56. To supportinfrared connections, an external IR communication device 355 is presenton the outside surface of device 100 d which communicates with acorresponding device 310 on the host computer system 56. Host computersystem 56 contains a communication port 325 which is directly connectedto a serial communication device 320 which is connected to serial line265. When device 100 d is connected to the host computer system 56 usingthe serial line, connector 108 a is coupled to line 265 (e.g., using thecradle 60). Serial port 325 may be a UART chip.

Portable device 100 d of FIG. 6A also contains an internal resource,e.g., a wireless modem 240 (which could also be a wireless radio device)that is coupled to communicate with processor 101 over an internalserial port 385. Device 240 may also communicate over a wireless networkfor exchange of information. Serial port 385 is a communication port andis coupled to processor 101 using n-bit bus 390. In one embodiment, port385 is a serial UART port of the well known type. It is appreciated thatthe serial port 385 is directly accessible by the processor 101 becausethe processor 101 is directly connected to the serial port 385.Therefore, the processor 101 may directly access the internal modem 240.

Portable device 100 d of FIG. 6A also contains another communicationport 380 that is externally accessible to the wired communicationinterface 108 a, and the wireless communication devices 355 and 360. Inone embodiment, the wireless communication devices 355 and 360 containrespective translators 392 and 394 for translating their communicationprotocols to a standard serial communication protocol which exists atbus 370. In this way, the information on bus 370 is always presentedaccording to the serial communication standard (e.g., RS/232) but couldalso be USB formatted. It is appreciated that the serial port 380 isdirectly connected to processor 101 by an n-bit bus 396. Port 380 may bea UART chip. In one embodiment, internal port 385 and externallyaccessible port 380 are serial communication ports. In this case, bus390 and bus 396 each contain a respective transmit line (Tx) and arespective receive line (Rx) according to the well known RS/232 serialinterface standard.

While the communication ports 380 and 385 are shown as separate devicesand separate from processor 101, in one embodiment, the communicationports could also be integrated within the processor 101.

It is appreciated that regardless of the communication link used toestablish communication link 550 between the device 100 d and the hostcomputer system 56, the internal communication port 385 is neverdirectly connected to serial port 380. Therefore, the host computersystem 56 is not able to directly access the internal modem 240 usingthe externally accessible port 380, according to the strict hardwaredesign.

FIG. 6B illustrates system 200 b including the bridge process 400 (or“software bridge” 400) in accordance with an embodiment of the presentinvention. The bridge process 400 is a software process implemented tobridge communications between externally accessible port 380 andinternal port 385, as shown graphically in FIG. 6B. By using the bridgeprocess 400, the present invention is able to provide indirect, buttransparent, communication between port 380 and port 385. The bridgeprocess 400 therefore makes the internal modem 240 accessible to thehost computer system 56 over communication link 550 via port 380. Bymaking the internal wireless modem 240 accessible to the host computersystem 56, the host computer system 56 can use the internal wirelessmodem 240 as a peripheral device, e.g., to connect to the Internetwirelessly.

An immediate attraction of using a wireless PDA 100 d as a wirelessmodem is based, in part, on the fact that the PDA user probably alreadyhas all of the needed hardware. The interface is very user friendlybecause the PDA 100 d is routinely connected to the host computer system56 for synchronization. This same link can then be used for accessingthe wireless modem 240 of the PDA 100 d. In other words, unlike awireless phone, PDAs generally come with a cable attachment to the hostcomputer system 56. Any wireless PDA 100 d in its cradle can thenreadily be used as a wireless modem by a host computer system 56connected to the device 100 d via some connection 550. This network isuseful for most host computer systems and is especially valuable forlaptops.

It is appreciated that the bridge process 400 need not be integratedinto the operation system (OS) of device 100 d, but could readily existas a free standing application. Generally, the bridge process 400 maybehave in one of two different modes. First, the PDA 100 d may use awireless radio 240 that looks like a modem (e.g., a GSM chipset) and thesoftware 400 then acts as a bridge between the transport to the hostcomputer system 56 and the transport to the modem 240 (e.g., a layer twobridge). Second, the PDA 100 d may use a wireless radio that does notlook like a modem (like certain GPRS chipsets). In these cases, the PDA100 d may act as a termination point for the PPP link to the hostcomputer system 56. The PDA 100 d may then perform translation of IP(layer 3) data from the PPP link to the link layer used by the radiodevice 240. These different scenarios are described further below.

FIG. 7 illustrates a flow diagram of steps 400 performed by processor101 to implement the software bridge 400. It is appreciated that process400 may be implemented as software code stored in computer readablememory units of device 100 d and executed by processor 101. At step 405,if the bridge software is invoked, then step 410 is entered. Process 400can be invoked automatically by detecting certain commands and/or dataover communication link 550. Alternatively, process 400 can be invokedby a user launching the application from the OS.

At step 410, the processor 101 reads commands and data from the receiveline (Rx) of the externally accessible communication port (S1) 380. Atstep 415, the processor 101 then relays or copies these commands anddata to the transmit line (Tx) of the internal communication port (S2)385. This supports the transparent flow of information from the hostcomputer system 56 to the wireless modem 240. At step 420, the processor101 reads commands and data from the receive line (Rx) of thecommunication port (S2) 385. At step 425, the processor 101 then relaysor copies these commands and data to the transmit line (Tx) of theexternally accessible communication port (S1) 380. This supports thetransparent flow of information from the wireless modem 240 to the hostcomputer system 56.

At step 430, if the bridge software is maintained, then step 410 isexecuted again. If not, then process 400 returns and the softwareenabled communication link between ports 385 and 380 is terminated.

FIG. 8, FIG. 9 and FIG. 10 illustrate different protocol diagrams inwhich no transport translation is required, in which modem transporttranslation is required and in which the software bridge performs thetransport translation. It is appreciated that the embodiments of thepresent invention described in FIG. 8, FIG. 9 and FIG. 10 are applicablebetween any two transports, e.g., transport A and transport B. For sakeof discussion, PPP-transport (transport A) and non-PPP transport(transport B) have been selected as examples only. Other transportscould be used, e.g., SLIP and many well known others.

FIG. 8 illustrates a communication environment 500 in which embodimentsof the present invention may operate. Communication network 500 istransport A, e.g., PPP (point-to-point protocol) end-to-end, in that aPPP server 510 communicates to a PPP client 56. This is shown in theprotocol legend 560. In this network, a PDA 100 d is coupled as awireless modem peripheral to a host computer system 56 using a link 550.An Internet service provide (ISP) 510 acts as the PPP server whichcommunicates over a physical link 540 to a wireless base station 515.Base station 515 wirelessly communicates 530 to the wireless modem 240inside device 100 d. Wireless modem 240 is PPP compliant and thereforeno transport translation is required. Software bridge 400 maintains atransparent link between the internal port of the wireless modem and theexternally accessible connection 520 (e.g., IR 355, BT 360 or serial 108a). This is done using PPP. A link 550 then carries commands and data tothe host computer system 56 which is the PPP client.

FIG. 9 illustrates another communication environment 600 that is similarto environment 500 of FIG. 8 except that in environment 600 the ISP 510and the wireless base station 515 are not PPP compliant, as shown by theprotocol legend 610. A transport B, e.g., non-PPP transport, forexample, is WCDMA. In this case, the device 100 d is not a PPP client.Therefore, the modem 240 performs a translation between the non-PPPtransport received over wireless link 530 and a PPP compliant transportsupplied to the software bridge 400 (and vice-versa). This translationis well known. As a result, the device 100 d acts a PPP server. A PPPcompliant transport is then supplied over link 550 to the host computer56 which acts a PPP client.

FIG. 10 illustrates another communication environment 700 that issimilar to environment 600 of FIG. 9 except that the software bridge 400performs the required translation, not the wireless modem 240. Thistranslation is well known. The modem 240 is therefore fully PPPnon-compliant (e.g., is transport B complaint). The resulting protocollegend 710 is shown. In this case, the device 100 d is transport Bcompliant, e.g., not a PPP client. Therefore, the software bridge 400performs a translation between the non-PPP transport received from themodem 240 and a PPP compliant transport supplied over link 550 (andvice-versa). As a result, the device 100 d acts a PPP server. A PPPcompliant transport is then supplied over link 550 to the host computer56 which acts a PPP client.

The preferred embodiment of the present invention, a method and systemfor using a wireless enabled portable computer system as a wirelessmodem peripheral for a host computer system, is thus described. Whilethe present invention has been described in particular embodiments, itshould be appreciated that the present invention should not be construedas limited by such embodiments, but rather construed according to thebelow claims.

1. A method of allowing a host computer to use an electronic device as aperipheral comprising: receiving first commands and data over acommunication link at a first communication port of said electronicdevice; copying said first commands and data to a second communicationport internal to said electronic device. an internal wireless modemreceiving said first commands and data from said second communicationport; said internal wireless modem sending second commands and data tosaid second communication port; and copying said second commands anddata from said second communication port to said first communicationport.
 2. A method as described in claim 1 further comprising saidtransmitting said second commands and data from said first communicationport to said host computer system.
 3. A method as described in claim 1wherein said first communication port and said second communication portare serial communication ports.
 4. A method as described in claim inclaim 3 wherein said serial communication ports are implemented usingUART circuitry.
 5. A method as described in claim 1 wherein saidelectronic device is a personal digital assistant and wherein said firstcommunication port is for communicatively coupling said personal digitalassistant to said host computer system.
 6. A method as described inclaim 1 further comprising relaying information from a receive line (Rx)of said first communication port to a transmit line (Tx) of said secondcommunication port.
 7. A method as described in claim 1 furthercomprising relaying information from a receive line (Rx) of said secondcommunication port to a transmit line (Tx) of said first communicationport.
 8. A method as described in claim 1 further comprising said bridgeprocess performing protocol translation between a PPP communicationprotocol and a non-PPP communication protocol.
 9. A method as describedin claim 1 further comprising said wireless modem performing protocoltranslation between a PPP communication protocol and a non-PPPcommunication protocol.
 10. A method as described in claim 1 whereinsaid first communication port is a wireless Bluetooth compliant externalcommunication device for communicating with said host computer system.11. A method as described in claim 1 wherein said first communicationport is a wireless infrared external communication device forcommunicating with said host computer system.
 12. A method as describedin claim 5 further comprising communicatively coupling said hostcomputer system to said electronic device at said first communicationport of said electronic device.
 13. A method as described in claim 1further comprising a host computer system issuing said first commandsand data over said communication link to said electronic device using afirst communication port of said electronic device.
 14. A method asdescribed in claim 1 wherein said copying said first commands and datato a second communication port internal to said electronic device isperformed by a bridge process implemented in said electronic device. 15.A method as described in claim 14 wherein said copying said secondcommands and data from said second communication port to said firstcommunication port is performed by said bridge process.
 16. A method asdescribed in claim 1 wherein said second communication port is directlyaccessible to said host computer system.